Hi. I’m Cindy Starr. At NASA’s Scientific Visualization
Studio we work with many Earth science
datasets that must be accurately positioned on a globe.
For example, we obtained 30-meter topography data for Greenland
along with an ocean and an ice sheet mask from the Greenland Ice
Mapping Project at Ohio State. Each of these datasets
consists of a 6 x 6 array of 124
megapixel tiles. We also received seven sets of 20-meter
Radarsat data from the Canadian Space Agency,
mosaicked at the University of Washington‘s Applied Physics Lab.
Each set consist of a 5 x 5 array of
421 megapixel tiles. We developed
an IDL routine that extracts the coordinate and projection
information from geo-tif images and writes out RSL
include files that pass the parameters to a projection routine.
The projection routine is a C++ Renderman plugin
that computes the projection calculations in double precision
and accurately positions the related texture tile.
Parameters to the projection plugin are passed in string format in order to
provide double precision accuracy. We employed this method with
the high-resolution Greenland data, accurately mapping 87
gigapixels of data.